Characterization of cassava production in the Igarapé-Açu community, Capitão Poço, Pará, Brazil
Samara Ketely Almeida de Sousa¹*, Helen Patrícia Moreira Negrão¹, Letícia do Socorro Cunha², Thiago Feliph Silva Fernandes³, Júlia Karoline Rodrigues das Mercês³, Wanderson Cunha Pereira⁴, Edmilson Barbosa do Nascimento¹, Marlon Sheldon da Silva Galdino¹ and Amanda Catarine Ribeiro da Silva^1
1 Federal Rural University of the Amazon, Capitão Poço, PA, Brazil
² State University of Western Paraná, Marechal Cândido Rondon, PR, Brazil
³ Paulista State University Júlio Mesquita de Filho, Jaboticabal, SP, Brazil
⁴ Federal University of Pará, Bragança, PA, Brazil

Abstract
The objective was to characterize the cultivation of cassava by rural producers in the Igarapé-Açu community, in the municipality of Capitão Poço, Pará, Brazil. The research involved quali-quantitative methods. For this purpose, 45 semi-structured questionnaires were applied, which included all the cassava flour producers in the Vila, in order to obtain information about the cassava and cassava flour production system, such as: size of the cultivation area, varieties used, labor used and ways of preparing the soil for cultivation. Most respondents are small farmers with an area of less than 5 ha. The cassava variety most cultivated by farmers in the village of Igarapé-Açu is mullet and about 56% of producers use exclusively family labor. As for the preparation of the soil, 40% of the interviewees perform the felling and burning. This form of tillage predominates due to the absence of technologies and causes the soil to be degraded more quickly.

Highlighted Conclusions
1. The predominant farming areas characterize family farming.
2. Producers prefer to use the mullet variety because it is easy to adapt to the region.
3. Soil preparation is still incipient in terms of the technologies used for conservationw.
(more…)

Socioeconomic profile of cassava flour producers: a study on Vila de Igarapé-Açu, Capitão Poço, Pará, Brazil
Samara Ketely Almeida de Sousa¹*, Helen Patrícia Moreira Negrão¹, Letícia do Socorro Cunha², Thiago Feliph Silva Fernandes³, Júlia Karoline Rodrigues das Mercês³, Wanderson Cunha Pereira⁴, Edmilson Barbosa do Nascimento¹, Marlon Sheldon da Silva Galdino¹ and Amanda Catarine Ribeiro da Silva^1
1 Federal Rural University of the Amazon, Capitão Poço, PA, Brazil
² State University of Western Paraná, Marechal Cândido Rondon, PR, Brazil
³ Paulista State University Júlio Mesquita de Filho, Jaboticabal, SP, Brazil
⁴ Federal University of Pará, Bragança, PA, Brazil

Abstract
The objective of this work was to characterize the socioeconomic profile of cassava flour producers, in Vila de Igarapé-Açu, Capitão Poço, Pará, Brazil. The research involved quali-quantitative methods. To this end, 45 semi-structured questionnaires were applied to all producers of manioc flour in the Vila. The questions were asked in order to obtain information about the producers’ socioeconomic profile, such as: place of birth, age, education level and sources of income. The majority of respondents, about 69%, are from the village and only 31% are from other nearby locations, mainly from the municipality of Ourém, to which the village had belonged a few years ago. Regarding the age of the interviewed producers, there was a variation between 18 and 86 years, which provides a range of 68 years. The level of education among producers is considered low, since the majority, corresponding to 73%, has not completed elementary school. About 64% earn their income entirely through the production of manioc flour. The community has the majority of Vila’s natural flour producers, with a predominant age group between 41 and 50 years old. In addition, cassava flour production is the main source of income for most of the majority of respondents.

Highlighted Conclusions
1. Most producers are from the community itself.
2. The age range of producers is 68 years old.
3. The level of education is low.
4. Flour production is the main source of income for family farmers. (more…)

Response of white oat genotypes to water stress
Danyela de Cassia da Silva Oliveira, Solange Ferreira da Silveira Silveira, Rafael Valladao Fagundes, Daiana Doring Wolter, Frederico Madabula, Victoria Freitas de Oliveira, Artur Teixeira de Araujo Jr., Clause Fatima Brum Piana, Luciano Carlos da Maia and Antonio Costa de Oliveira
Federal University of Pelotas, Pelotas, RS, Brazil

Abstract
White oat is generally cultivated in areas where there is no problem with water deficit, but due to the expansion of the cultivated areas and climate changes, there is a concern to characterize the genotypes response to water stress. The objectives of this work were to study the variability of responses of white oat cultivars, when subjected to different levels of osmotic potentials and to evaluate the genetic dissimilarity between these, with the use of REMAP markers. To study the variability, two experiments with completely randomized design, conducted in growth chambers were performed, where several oat genotypes in different osmotic potentials were evaluated. To evaluate the dissimilarity among the cultivars, REMAP markers were used. The experiments suggested the characteristics shoot (SL) and root (RL) length as the most affected by the stress. The use of the markers indicated that the similarity among the cultivars varies between 0.80 and 0.58. The study points out the cultivars URS 21, URS Corona, URS Fapa Slava as being those with the highest level of tolerance to water stress.

Highlighted Conclusions
1. The 0.8 MPa dose allows the discrimination of cultivars by performance against water stress.
2. The cultivars URS 21, URS Corona and URS Fapa Slava show better performance under water stress. (more…)

Allelopathy of weeds on the growth of vegetables
Ines Rezendes¹, Ediane Roncaglio Baseggio¹, Leandro Galon¹, Daiani Brandler¹, César Tiago Forte¹, Ignacio Aspiazú², Milena Barretta Franceschetti¹ and Alexandre Ferreira da Silva^3
1 Federal University of Fronteira Sul, Erechim, RS, Brazil.
² State University of Montes Claros, Janaúba, MG, Brazil.
³ Embrapa Milho e Sorgo, Sete Lagoas, MG, Brazil.

Abstract
The use of allelopathy emerges as an alternative method for weed management in crops, especially in small vegetable producing properties. Thus, the objective of this work was to identify possible allelopathic effects of aqueous extracts of the weeds Cyperus difformis L. (small-flowered nutsedge), Commelina benghalensis L. (benghal dayflower) and Galinsoga parviflora Cav. (gallant soldier) on seed germination and seedling growth of Lactuca sativa L. (lettuce) and Lycopersicum esculentum L. (tomato). Two experiments were carried out in a completely randomized design with five replications, the first with lettuce seeds and the second with tomato seeds submitted to germination in five concentrations of weeds aqueous extracts (0, 25, 50, 75 and 100%). All treatments with aqueous extracts of the three species, at different concentrations, caused a reduction in lettuce and tomato root length. There was a reduction in most of the evaluated variables, and seed germination of the crops had the lowest influence of the extracts. The weeds benghal dayflower, small-flowered nutsedge and gallant soldier showed allelopathic potential on lettuce and tomato crops. This potential allelopathic effect is directly related to the concentration and type of extract from the plant species. In general, it can be noted that the greatest allelopathic effect occurred with the use of small-flowered nutsedge extract, followed by gallant soldier and benghal dayflower.

Highlighted Conclusions
1. Weeds C. benghalensis, C. difformis and G. parviflora show allelopathic potential on the growth of L. sativa and L. esculentum.
2. Highest allelopathic effect is caused by the extract of C. difformis, followed by G. parviflora and C. benghalensis.
3. The potential allelopathic effect of weeds is directly related to the plant species used, as well as to the concentration of the aqueous extract present in the environment. (more…)

Associations between agronomic performance and grain chemical traits in oat
Solange Ferreira da Silveira Silveira, Danyela de Cassia Silva Oliveira, Latoia Eduarda Maltzhan, Tiago Corazza, Victoria Freitas de Oliveira, Cristiano Stulp, Henrique Pasqueti Carbonari, Vianei Rother, Maraisa Crestani Haverroth, Luis Carlos Gutkoski, Luciano Carlos da Maia and Antonio Costa de Oliveira
Federal University of Pelotas, Pelotas, RS, Brazil

Abstract
Great progress has already been achieved in breeding white oats (Avena sativa L.). However, breeders of this species need to make available to the market higher yielding and higher grain quality cultivars. Therefore, it is necessary to optimize the strategies of selection of superior genotypes. The present work aimed to estimate the correlation between traits related to agronomic performance and traits related to chemical composition of white oat grains, seeking to add understanding for the selection of higher yielding genotypes with high nutritional quality. Thirty families from the cross between the cultivars Albasul and UPF 15 were used, and 31 families from the cross between the cultivars IAC 7 and UFRGS 19. Six traits related to agronomic performance and five traits corresponding to the chemical composition of the grains were evaluated. To assess the relationship between the different traits evaluated, simple correlation and canonical correlation analyzes were performed. The results demonstrate the existence of simple correlations between grain chemical constituents and traits related to agronomic performance. The pair-by-pair relationship between traits of these two groups was also observed, but the environmental action strongly interfered with these correlations. The canonical correlation analysis allowed the verification of dependence between the evaluated trait groups where genotypes with higher number of grains per panicle, high mass of one thousand grains, with lower stature and lower number of spikelets, will have lower lipid and total fiber content, but with higher protein contents.

Highlighted Conclusions
1. There is a relationship of dependence between the agronomic performance trait group and the oat grain chemical constituent group.
2. Indirect selection of grains with higher nutritional quality and high agronomic performance will be feasible providing there is a strict control of environmental conditions.
3. Selections that seek superiority in all traits studied will not be possible, given the presence of negative correlations. (more…)

Communications in Plant Sciences, vol 9, p. 129-132, 2019 (2019021)
DOI: http://dx.doi.org/10.26814/cps2019021

Control of water hyacinth: a short review

Wilson Roberto Cerveira Junior and Leonardo Bianco de Carvalho*
*Correspondence to: leonardo.carvalho@unesp.br

Abstract: Water hyacinth (Eichhornia crassipes) is an aquatic weed native from South America that invades waterbodies of tropical and sub-tropical sites worldwide. Mechanical, chemical and biological efforts are been used to control water hyacinth. Each method of control shows advantages and disadvantages. There are no water‐use restrictions associated with mechanical control and it does not require much technical expertise, especially when plants are removed from the waterbody. However, changes in dissolved oxygen and trophic structure can accelerates eutrophication when plants are cut, leading to a subsequent increase in water hyacinth blooms. Chemical control is less labor intensive and expensive than mechanical control, especially at large scales. However, herbicides can kill non‐target algae and non‐target macrophytes, resulting in far reaching ecological impacts. Biological control is an alternative to mechanical and chemical control. It is not labor or equipment intensive, and has the potential to be self‐sustaining. However, host specificity is critical to the success of biological control and the and long-term results can discourage one to use this method. Probably, biological control is the most efficient and safety method for water hyacinth management, especially for long-term results. Mechanical and chemical control are effective for short-term results, but they can seriously impact on ecological conditions of waterbodies.

Highlighted Conclusion
1. Mechanical, chemical and biological methods are efficient to control water hyacinth.
2. Biological control is very efficient and safety for long-term control of water hyacinth.

Keywords: Eichhornia crassipes, Aquatic weed, Macrophyte, Weed control. (more…)

Communications in Plant Sciences, vol 9, p. 124-128, 2019 (2019020)
DOI: http://dx.doi.org/10.26814/cps2019020

Reaction of rice cultivars to Meloidogyne graminicola as a function of irrigation management

Cristiano Bellé*, Rodrigo Ferraz Ramos, Ricardo Rubin Balardin, Tiago Edu Kaspary and Andressa Lima De Brida
*Correspondence to: crbelle@gmail.com

Abstract: The objective of this study was to evaluate the reproduction of Meloidogyne graminicola in 22 cultivars of rice used in the southern region of Brazil according to the irrigation management. The design was completely randomized in a factorial scheme, being the factor A: rice cultivars and factor B: irrigation management (dry and flooded). The rice cultivars were kept individually in pot with sterilized substrate and inoculated with 5,000 eggs and juveniles (second stage – J2) of the nematode. Plants to rice cultivate BRS IRGA 410 was inoculated with M. graminicola and were used as controls. At 60 days after inoculation, the root system of each plant was evaluated number of galls (NG), number of nematodes per gram root (NNGR) and the reproduction factor (RF). The results demonstrate that M. graminicola can parasitize and develop in different rice cultivars that are commonly used in commercial crops in the Southern region of Brazil, and all cultivars evaluated were classified as susceptible to this nematode (FR> 1.00). The cultivation system under flood conditions showed significantly lower values for the NG, NNGR and RF.

Highlighted Conclusions
1. The cultivars BRS Firmeza, IRGA 421, IRGA 423, IRGA 424, IRGA 436, IRGA 428 CL, IRGA 429, Inov CL, Avaxi CL, BRS Catiana and SCS121 CL showed the lowest RF in the flooded crop.
2. The use of cultivars with lower nematode RF in early flood cropping systems is a strategy indicated to reduce the population and the potential for damage caused by M. graminicola in areas with rice crop.

Keywords: Root-knot nematodes, Reproduction, Susceptibility, Oryza sativa. (more…)

Communications in Plant Sciences, vol 9, p. 115-123, 2019 (2019019)
DOI: http://dx.doi.org/10.26814/cps2019019

Azospirillum brasilense and macronutrients in the initial establishment of brachiaria

Tauane Santos Brito*, Tatiane Eberling, Leila Alves Netto, Giovana Ritter, Renan Pan, Daniele Cristina Schons Eckhardt and Vandeir Francisco Guimarães
*Correspondence to: tauane.brito@unioeste.br

Abstract: Pasture production needs sustainable technologies, associating correct fertilization techniques that allow its maintenance aiming at productivity for quality animal feed production. The objective was to evaluate the initial responses of the inoculation with Azospirillum brasilense associated to macronutrients in Brachiaria brizantha cv. ‘Xaraés’. In pots filled with Oxisoil, with combinations of macronutrients as formulates (10-10-10; 20-10-10; 10-20-10; and 10-10-20) associated or not to inoculation with growth promoting bacteria A. brasilense, the experiment was conducted in a randomized blocks design, with four replicates. At 10, 20 and 30 days after emergence the plants were evaluated for number of leaves, length of the biggest leaf, aerial length, number of tillers and chlorophyll relative content. At 30 days after emergence, plants were evaluated for dry mass of roots and aerial part, root length, leaves content of nitrogen, phosphorus and potassium. The use of the formula 10-20-10, in the absence or presence of inoculation with A. brasilense, increased the leaves initial development of plants of B. brizantha cv. ‘Xaraés’. The formula 10-10-10, in the absence and presence of bacterial inoculation, resulted in plants with lower foliar development up to 30 days after emergence.

Highlighted Conclusion
The nutritional availability influences in the initial development of seedlings of B. brizantha cv. ‘Xaraés’.

Keywords: Nitrogen, Phosphorus, Potassium, Pastures, Growth promotion. (more…)

Communications in Plant Sciences, vol 9, p. 108-114, 2019 (2019018)
DOI: http://dx.doi.org/10.26814/cps2019018

Phenology and phytomass of Crotalaria incana L. in the Eastern Amazon, Brazil

Renata Thaysa da Silva Santos*, Mailson Freire de Oliveira, Vandeilson Belfort Moura, Yanna Karoline Santos da Costa and Rafael Gomes Viana
*Correspondence to: renata.thaysa@unesp.br

Abstract: Crotalaria incana presents alkaloids that, when ingested by ruminants, culminates in the death of the animals. Given the problems surrounding the presence of the plant in pasture areas, the objective of this research was to determine the phenology and development of C. incana plants under controlled conditions in the Eastern Amazon. The experimental design was completely randomized with four replications and eight treatments. The treatments consisted of plant collection times, from 20 to 160 days after plant emergence. The following parameters were evaluated: number of leaves, leaf length, plant height, number of flowers, number of pods, number of seeds per pod, total number of nodules and nodule viability, in addition to dry weight of shoots, roots, flowers and pods. Data were undergoing regression analysis and simple linear Pearson correlation. The vegetative and reproductive phase lasted until 60 and 140 after emergence, respectively. Plant management should be performed within 80 days of emergence.

Highlighted Conclusions
1. The vegetative state lasts up to 60 days after emergence; at this interval, the species can be incorporated into the soil without risk of increasing the emergence flow of the plant.
2. Control of the species on pasture should be performed before 80 days after emergence.

Keywords: Green manure, Control, Shakeshake, Pasture. (more…)

Communications in Plant Sciences, vol 9, p. 100-107, 2019 (2019017)
DOI: http://dx.doi.org/10.26814/cps2019017

Nitrogen and potassium sources of fertilizers may affect wheat blast and Fusarium head blight under favorable weather conditions

Sérgio Ricardo Silva*, Adriano Augusto de Paiva Custódio, José Salvador Simonetto Foloni and Manoel Carlos Bassoi
*Correspondence to: sergio.ricardo@embrapa.br

Abstract: Wheat blast (WB) and Fusarium head blight (FHB) are important wheat spike diseases in South America. There is evidence that the severity of these diseases is influenced by soil fertilization. The effects of nitrogen (N) and potassium (K) sources of fertilizers and phenological stages for topdressing fertilization on these spike diseases were evaluated during the 2015 and 2016 winter seasons in an endemic area for these diseases in Brazil. Two distinct field experiments were carried out, one focusing on N sources and the other on K sources. The experimental design was a complete randomized blocks, with four replicates, and the treatments were disposed in a 2 x 3 x 3 factorial: two wheat genotypes (BRS Gaivota and BRS Gralha-Azul), three sources of N or K, and three phenological stages for fertilization. The WB and FHB severities in BRS Gralha-Azul were higher than that in BRS Gaivota. FHB severity was lower when N was applied in the booting stage than in flowering. The sources of K influenced FHB severity, which was higher when K chloride was applied, compared with K nitrate. The weather condition was the determining factor in the wheat expression to WB and FHB diseases, followed by genotype resistance.

Highlighted Conclusions
1. Nitrogen and K sources of fertilizers and the phenological stages for N and K fertilizations do not play a significant role on wheat expression to WB and FHB.
2. Weather condition is the determining factor in the wheat expression to WB and FHB, followed by genotype resistance.

Keywords: Triticum aestivum, Magnaporthe oryzae Triticum pathotype, Fusarium graminearum, Wheat spike diseases, Nutrient-plant disease interaction. (more…)